With rapid development of display technologies, touch display panels have been increasingly popular among users. Depending on their structures, the existing touch display panels include add-on type touch display panels, on-cell touch display panels and in-cell touch display panels. In the in-cell touch display panel, touch electrodes for a touch sensing function are embedded in the liquid crystal display panel to reduce the overall thickness of the touch display panel and also significantly decrease manufacturing costs of the touch display panel, thus the in-cell touch display panels are favored by touch display panel manufacturers.
In the existing in-cell touch display panel, an array substrate includes a common electrode layer which is generally divided into a plurality of common electrode blocks, which may be reused (or driven, or operable) as touch electrodes, and each of the common electrode blocks is electrically connected with a drive chip by a metal wiring electrically insulated from other common electrode blocks. In particular, the metal wiring is electrically connected with the corresponding common electrode block by a bridge structure. Since the bridge structure is disposed in the same layer as the pixel electrode, and is maintained at an electric potential that is the same as that of the corresponding common electrode block because the bridge structure is electrically connected with the common electrode block, an additional electric field formed between the pixel electrode and the bridge structure is added to an existing electric field formed between the common electrode block and the pixel electrode, thereby causing differences of electric field distribution between a region with the bridge structure and a region without the bridge structure above the metal wiring, and hence causing differences of brightness between the region with the bridge structure and the region without the bridge structure in the display panel, so that the overall display brightness of the display panel is non-uniform.